Bone fractures are repaired by inserting bone fracture reduction rods or intramedullary nails into the intramedullary canal of a bone in order to stay the fracture. In performing this type of surgery for femoral fractures for example, it is conventional to make an incision near the tip of the greater trochanter extending proximally in line with the fibers of the gluteus in order to create an entry portal through the bone and into the canal. However, it has been found to be difficult to correctly position the entry portal to the intramedullary canal from the greater trochanter and to ream the canal to the desired size without damaging the surrounding soft tissue, displacing the previously reduced fracture, or making extremely large incisions. This is especially true if the patient is obese or if flexion or abduction of the proximal fragment causes a portion of the greater trochanter to lie against the ilium.
In this type of surgery, after the entry portal has been established, the canal is progressively reamed to a larger diameter from a smaller diameter in increments of about 0.5 mm, from generally about 8 mm, up to generally about 12.5 mm. Typically, the surgeon starts with a small reamer, reams the bone, removes the reamer and then inserts a second reamer, 0.5 mm larger in diameter than the previous reamer. The surgeon repeats this process until he has reached the required canal diameter for the intramedullary nail that has been selected for the patient.
Additionally, this type of surgery can be particularly bloody which presents other problems. Excess blood can obstruct the surgeon's view of the site being reamed and excessive blood flowing from the surgical site can create problems for the surgical staff particularly if the patient has a blood or bone disease. Thus, it is important that the surgical instrumentation provide for suctioning of the blood created by the surgery from the surgical site.
Several other problems are encountered during the process of repeatedly inserting the different sized reamers in and out of the bone. First, the surgeon can lose the entry portal, even though there may be a guide rod in place, as the soft tissues close around the slender guide rod, eliminating from view the entry portal opening. Further, as the reamers are slid over the guide rod and into the soft tissues, the sharp edges of each reamer rub against the soft tissues. Because this process is repeated a number of times during the reaming process, the soft tissues become very irritated and torn. Additionally, the guide rod can be pulled out of the bone when a reamer is being withdrawn.
A second problem has to do with the actual entry of the reamer into the intramedullary canal of the bone after it has passed through the soft tissues. Since the guide rod is so much smaller than the reamer (3 mm compared to at least 8 mm), the guide rod frequently will not stay centered in the opening created by the previous reamer, which results in the next reamer getting caught on the edge of the opening created by the previous reamer. Since the next reamer is larger in size, it will not fit smoothly into the opening created by the previous smaller reamer. This situation prevents the surgeon from being able to determine if the next larger reamer is correctly centered before he or she starts reaming the canal. In order for the surgeon to locate the opening with the present instrumentation, he typically has to make a larger incision in order to locate the entry portal and determine the correct centering of the reamers.
There have been a number of attempts to solve these problems. One attempt is found in U.S. Pat. No. 5,624,447 which describes a surgical tool guide and entry portal positioner that provides a cannulated sleeve with a handle and a C-shaped soft tissue protector secured to the sleeve. U.S. Pat. No. 5,569,262 describes a guide tool for surgical devices that is used for directing a surgical device into attachment with a bone segment and is used to protect a surgeon's fingers from the surgical device and from the jagged surface of the bone segment. U.S. Pat. No. 5,443,469 describes a tubular tissue protection guard that is inserted into an incision or wound in order to accommodate reaming devices.
While these devices provide protection to the soft tissues, none of them provide a working channel within the bone canal in which to progressively ream out the intramedullary canal of the bone. It would be advantageous to have a device that can be used to both open the entry portal into the canal of a bone and to provide a working channel in which to ream the canal of the bone in a minimally invasive mannor. It also would be advantageous to be able to use the subject invention in combination with an entry portal tool that can be used to locate the most desirable placement of the entry portal into the bone.